Laserfiche WebLink
��.✓ <br /> Nftww <br /> San Joaquin County <br /> Environmental Health Department DIRECTOR <br /> >.•'— <' .O Donna Heran, REHS <br /> Q % 600 East Main Street <br /> Stockton, California 95202-3029 PROGRAM COORDINATORS <br /> N { Robert McClellon,REHS <br /> • — Jeff Carruesco,REHS,RDI <br /> � <br /> . _ p Kasey Foley,REHS <br /> ;• <br /> .- FORS Website: www.sjgov.org/ehd Linda Turkatte,REHS <br /> Phone: (209)468-3420 <br /> Fax: (209)464-0138 <br /> April 14, 2011 <br /> Mr. Denis L. Brown <br /> Shell Oil Products US <br /> HSE— Environmental Services <br /> 20945 South Wilmington Avenue <br /> Carson, California 90810-1039 <br /> Subject: Interstate Shell <br /> 620 West Charter Way <br /> Stockton, California 95206 <br /> The San Joaquin County Environmental Health Department (EHD) has reviewed Site <br /> Investigation Report and Human Health Risk Assessment (SIR/HHRA), dated 08 December <br /> 2010, submitted by Conestoga-Rovers and Associates (CRA) on your behalf for the above- <br /> referenced site. <br /> Since 2008, CRA has identified and monitored groundwater beneath this site in the following <br /> three depth intervals: Zone A from 20 to 45 feet below surface grade (bsg), Zone B from 45 to <br /> 50 feet bsg, and Zone C from 65 to 90 feet bsg. By letter dated 13 July 2009, the EHD had <br /> directed the submittal of a feasibility study/remedial action plan in light of the analytical results <br /> reported quarterly for groundwater collected from the three zones. During a telephone <br /> conversation with the EHD on 19 November 2009, CRA had proposed an additional site <br /> investigation to further assess the distribution of petroleum hydrocarbon contamination prior to <br /> submitting a remedial action plan/corrective action plan (CAP). With these objectives, Site <br /> Investigation Work Plan, dated 21 December 2009, was submitted by CRA and approved by the <br /> EHD by letter dated 19 February 2010. The EHD had also directed by letter dated 21 May 2010 <br /> the submittal of a Human Health Risk Assessment (HHRA). <br /> In the SIR/HHRA, CRA documents the soil and groundwater analytical results and soil lithology <br /> from the advancement of five cone penetration test (CPT) borings to approximately 55 feet bsg, <br /> and the results from a separate investigation involving the sampling and analysis of <br /> groundwater for sodium at this site. During the advancement of CPT borings, soil samples were <br /> collected at 10 foot intervals to approximately 50 feet bsg and grab groundwater samples were <br /> collected at depth intervals between approximately 24 to 34 feet bsg (Zone A) and 46 to 51 feet <br /> bsg (Zone B). CRA also assessed the potential health risk posed by petroleum hydrocarbon <br /> concentrations detected at this site. Based on the soil and groundwater investigation and the <br /> HHRH, CRA concluded that: <br />